Hi
You need to be more specific...
What game, where did you get the installer, where is the game installed etc.
Did you make a DVD from the ISO file, how did you install it?
If we know more someone may be able to help because they have dealt with the issue before.
That said, the first thing I would do is completely uninstall the game using Revo Uninstaller,
http://www.revouninstaller.com/revo_uninstaller_free_download.html
and run CCleaner to clean up the left behinds (including the registry checker) and then try and install the game again.
Link Removed
When you try and reinstall it don't install it to the same directory that you did before.
This will keep Windows from picking up errors from the previous install and see...